Nuclear properties of stannum isotopes have been studied by the self-consistent shell-model-like approach in the framework Relativistic Mean Field theory, i.e., RMF+SLAP, and compared with the results from the non self-consistent RMF+SLAP* in which the influence of the pairing correlations on the mean field has been neglected. It is shown that the RMF+SLAP method can reproduce correctly the change of the quadrupole deformation as a function of pairing strength, the binding energy, one- and two-neutron separation energies and quadrupole deformation of stannum isotopes. The importance in treating the pairing correlations and block effect correctly has been emphasized.